Envelope for electric devices



Oct, 2, 1951 A. KQERBIS ENVELOPE FOR ELECTRIC DEVICES Filed Dec: 14, 1950 I N V EN TOR. A56 eff Aaenxb A TTORNEY Patented Oct. 2, 1951 2 5 9 723 2,569.72: nuvncorr. Fon ELECTRIC DEVICES Albert Koerbis, Irvington, N. J., assignor to Hanovia Chemical & Mamnacturing Company, Newark, N. J., a corporation of New Jersey Application December 14, 1950, Serial No. 200,129

4 Claims. 1

This invention relates to the sealing of conductors into or through envelopes of vitreous material and is concerned in particular with producing a. hermetically sealed envelope having seal-oil tip where it may be heated by connection currents, but expedients of this type involve many complications. and are not entirely satisfactory.

It is accordingly an object of this invention to avoid the above noted difllculties and to provide an envelope for an electric device with no seal-oil tip either in the wall or an end thereof. Further objects and various advantages of the invention will appear as the following description proceeds and by reference to the accompanying drawing in which Figures 1, 2, and 3 are sectional views of an end portion of an envelope for a vapor electric discharge device and show the several steps involved in practicing the method of forming a hermetically sealed envelope according to the invention.

For the purpose of illustration, I have chosen to describe the details of my invention by reference to a vapor electric discharge device of the type wherein a lead-in conductor is sealed in the envelope thereof by forming a bead of vitreous material around the conductor and sealing the bead into an opening in the end of the envelope.

I desire to have it understood, however, that this electric lead-in conductors but no seal-off tip. 5 illustration is not limitative or restrictive even In the manufacture of electrical devices, such of the vapor electric discharge devim contemas, for example, vapor electric discharge devices plated by this invention. The seal between the having envelopes of vitreous material, it is cuslead-in conductor and the envelope may be tomary to exhaust the envelope and fill it with a formed directly without the use of a bead. and the gas through a small tube in the wall thereof. 10 lead-in conductor may includeathin-foil portion After exhausing and, when desired, filling with of molybdenum or tungsten and the like for pura gas, the tube is sealed off by forming a tip that poses well known to those skilled in the art.

- protrudes from the envelope. A protruding seal- The envelope of the illustrated vapor discharge off tip on the wall of an envelope is, of course, device is indicated at l, and it may be formed troublesome since it is susceptible to being of quartz or special ultra-violet transmitting broken oil easily. To avoid this likelihood of glasses especially when the discharge device is damage to the envelope, seal-oil tips have often designed for emitting ultra-violet radiations. been formed in an end of the envelope, usually The envelope l is provided with a tubular neck near the lead-in conductor seal; however, even portion 2 at a position where it is desired to locate .when 0 located, a seal-oil tip is objectionable at least one of the lead-in conductors. Alead-in and special caps or bases must be provided to conductor in the form of a wire 3 is shown in the cover is drawing, and two spaced apart portions thereof Besides being liable to easy breaking off when are sealed in the beads 4 and 5. The beads l and not handled carefully, a seal-off tip on an en- 5 may consist of the vitreous material used to velope that becomes heated during operation is form the envelope i and the neck portion 2, or somewhat cooled by the surrounding air. wherethey may comprise one or more transition glasses upon it may crack or fracture the envelope due having graded expansion coeflicients which lie to unequal strains in the vitreous material that between the expansion coefllcients of quartz, i. e. forms the envelope and the seal-off tip. Furwhen the envelope is formed of quartz, and the thermore, in the case of, for example, metal metal of the lead-in wire 3.

vapor discharge lamps, coolin of the seal-off tip Figure 1 shows an exhausting or filling tube 6 causes the metal vapors to condense in the tip attached to the tubular portion 2 and communiwhich adversely affects the operation of the lamp. eating with the space within the envelope through To correct for the cooling of the seal-off tip, arthe opening 1' in the portion 2. After the enrangements have been proposed for locating the velope is closed by forming a temporary outer seal 8 around the bead 4, the envelope is exhaustedthrough the tube 6 and in the case of a mercury vapor discharge device, is filled with a'starting gas, such as argon, krypton and zenon, and a small quantity of mercury is passed into the envelope through the tube 6.

After the envelope has been filled as desired, the tube 6 is sealed-off forming a tip, as shown at 9 in Figure 2. No special precautions in forming the tip 9 need be taken, such as maintaining a critical size for the tip as has been required heretofore, since according to the invention the seal-off tip is entirely removed after it has served its purpose. Following this operation of filling and'sealing of the envelope, a second or final seal in like that shown at 8 is formed around head 5 by heating and pressing the tubular portion inwardly against the bead 5. Thereafter the tubular portion 2 may be broken off beyond the seal Ill and the lead-in wire 3 may be cut oil.

3 leaving a sealed-in conductor in an hermetically sealed envelope with no seal-oi! tip as shown in Figure 3.

From the above description, it will be seen that I have provided a simple and convenient method for forming an improved hermetically sealed electrical device. No exhaust tip appendage or remnant remains as part of the complete envelope whereby likelihood of damage thereto, through breakage of the tip, is eliminated.

It is understood, of course, that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What I claim is:

1. The method of manufacturing an hermetically sealed envelope of vitreous material for an electrical device comprising the steps of sealing an elongated portion oi! said envelope around a lead-in wire, providing a tube on said elongated portion, filling said envelope with an ionizable medium through said tube, sealing off said tube,

and forming a second seal around said lead-in wire at a location between said tube and the main portion of said envelope.

2. The method of manufacturing an hermetically sealed envelope of vitreous material for an electrical device comprising the steps of positioning a lead-in conductor in a tubular end of said envelope, fusing said tubular end around said conductor, filling said envelope with an ionizable medium through an opening in said tubular end located inwardly of said fused portion, sealing-oi! said opening, fusing said tubular end around said conductor at a location inwardly of said sealed-oil opening, removing that portion of said tubular end that extends beyond the inner seal.

' 3. The method of manufacturing a vapor discharge device having an envelope of vitreous material comprising the steps of ositioning a leadin conductor in a tubular extension of said envelope, forming a temporary seal between said extension and said conductor, filling said envelope through an opening in said extension arranged inwardly of said temporary seal, sealing oi! said opening, forming a dual seal between said extension and said conductor at a location inwardly of said opening, and removing that portion of said extension that extends beyond said final seal.

4. The method or manufacturing a vapor discharge device having an envelope of quartz, comprising the steps 01' forming a tubular extension of quartz on said envelope and an exhausting and filling tube on and intermediate the ends of said tubular extension, arranging in said extension a lead-in conductor of a length that is greater than said extension whereby said conductor extends from within the outer end of said extension to within said envelope for carrying an electrode sealing said outer end of said extension around said conductor, exhausting said envelope and said extension through said tube, filling said envelope and said extension with a rare gas and passing a small quantity 0! vaporizable metal into said envelope through said tube, closing said tube, sealing the inner end of said extension around said conductor, and removing that portion of said extension that extends beyond said last mentioned seal.

ALBERT KOERBIS.

No references cited. 

